Vascular Protective Effects of Xanthotoxin and Its Action Mechanism in Rat Aorta and Human Vascular Endothelial Cells

Xanthotoxin, a novel inducer of platelet formation, promotes thrombocytopoiesis via IL-1R1 and MEK/ERK signaling

BACKGROUND

Thrombocytopenia is a common hematological disease caused by many factors. It usually complicates critical diseases and increases morbidity and mortality. The treatment of thrombocytopenia remains a great challenge in clinical practice, however, its treatment options are limited. In this study, the active monomer xanthotoxin (XAT) was screened out to explore its medicinal value and provide novel therapeutic strategies for the clinical treatment of thrombocytopenia.

METHODS

The effects of XAT on megakaryocyte differentiation and maturation were detected by flow cytometry, Giemsa and phalloidin staining. RNA-seq identified differentially expressed genes and enriched pathways. The signaling pathway and transcription factors were verified through WB and immunofluorescence staining. Tg (cd41: eGFP) transgenic zebrafish and mice with thrombocytopenia were used to evaluate the biological activity of XAT on platelet formation and the related hematopoietic organ index in vivo.

RESULTS

XAT promoted the differentiation and maturation of Meg-01 cells in vitro. Meanwhile, XAT could stimulate platelet formation in transgenic zebrafish and recover platelet production and function in irradiation-induced thrombocytopenia mice. Further RNA-seq prediction and WB verification revealed that XAT activates the IL-1R1 target and MEK/ERK signaling pathway, and upregulates the expression of transcription factors related to the hematopoietic lineage to promote megakaryocyte differentiation and platelet formation.

CONCLUSION

XAT accelerates megakaryocyte differentiation and maturation to promote platelet production and recovery through triggering IL-1R1 and activating the MEK/ERK signaling pathway, providing a new pharmacotherapy strategy for thrombocytopenia.

Mechanistic Study of Xanthotoxin-Mediated Inactivation of CYP1A2 and Related Drug-Drug Interaction with Tacrine

Xanthotoxin (XTT) is a biologically active furanocoumarin widely present in foods and plants. The present study is designed to systematically investigate the enzymatic interaction of XTT with CYP1A2, along with pharmacokinetic alteration of tacrine resulting from the co-administration of XTT. The results showed that XTT induced a time-, concentration-, and NADPH-dependent inhibition of CYP1A2, and the inhibition was irreversible. Co-incubation of glutathione (GSH) and catalase/superoxide dismutase was unable to prevent enzyme inactivation. Nevertheless, competitive inhibitor fluvoxamine exhibited a concentration-dependent protective effect against the XTT-induced CYP1A2 inactivation. A GSH trapping experiment provided strong evidence for the production of epoxide or/and γ-ketoenal intermediates resulting from the metabolic activation of XTT. Furthermore, pretreatment of rats with XTT was found to significantly increase the C_max and area under the curve of plasma tacrine relative to those of tacrine administration alone.

Antioxidant activity, analgesic activity, and phytochemical analysis of Ammi majus (L.) extracts

Ammi majus (L.) is commonly used to cure many diseases in Moroccan folk medicine, especially vitiligo. This research tries to evaluate the phytochemical constituents of two aqueous extracts (E1; Maceration; 48 h) and (E2: Infusion; 1h) and three organic fractions (F1: Cyclohexane), (F2: Ethyl acetate (EtOAc)) and (F3: Ethanolic (EtOH)) of A. majus (L.) seeds, as well as to study the antioxidant and analgesic activity of the species. Phytochemical analysis, antioxidant activity (DPPH, FRAP, ABTS, and TAC tests), and analgesic activity (writhing and tail immersion were induced by Acetic acid tests) were analyzed according to the literature. A quantitative phytochemical study indicate that the E1 had the highest content of total polyphenols (26.95 ± 0.53 mg GAE/g extract) and flavonoids (37.92 ± 0.46 mg QE/g extract), while F3 showed a promising flavonol content (24.26±0.08 mg QE/g extract). Tannins were found to be high in F1 (59.27 ± 0.16 mg CE/g extract) and F2 (57.65 ± 1.18 mg CE/g extract). Antioxidant results reveals that DPPH (IC50 = 179.68 ± 0.47 μg/mL) and FRAP (EC50 = 367.03 ± 0.12 μg/mL) show to E1 a high antioxidant activity. Regarding the analgesic activity of the different studied extracts, it was found that E1 has a high peripheral analgesic effect with 62.32 % and a high central analgesic potential throughout the experimentation at 500 mg/kg. Our studies demonstrated for the first time that A. majus seeds extracts have high antioxidant and analgesic activities through different analysis techniques.

Design, synthesis and biological evaluation of dehydroabietic acid derivative as potent vasodilatory agents

Using dehydroabietic acid as the lead compound for structural modification, 25 dehydroabietic acid derivatives were synthesized. Among them, compound D1 not only showed the strongest relaxation effect on the aortic vascular ring in vitro (Emax = 99.5 ± 2.1%, EC50 = 3.03 ± 0.96 µM), but also significantly reduced systolic and diastolic blood pressure in rats at a dose of 2.0 mg/kg in vivo. Next, the vascular protective effect of the best active D1 and its molecular mechanism were further investigated by HUVECs. The results showed that D1 induced endothelium-dependent diastole in the rat thoracic aorta in a concentration-dependent manner. Endothelium removal or aortic ring pretreatment with NG-nitro-l-arginine methylester (l-NAME), 1H-[1,2,4]-oxadiazolo-[4,3-a]-quinoxalin-1-one (ODQ), and tetraethylammonium (TEA) significantly inhibited D1-induced relaxation. In addition, wortmannin, KT5823, triciribine, diltiazem, BaCl2, 4-aminopyridine, indomethacin, propranolol, and atropine attenuated D1-induced vasorelaxation. D1 increased the phosphorylation of eNOS in HUVECs Furthermore, D1 attenuated the expression of TNF-α-induced cell adhesion molecules such as ICAM-1 and VCAM-1. However, this effect was attenuated by the eNOS inhibitors l-NAME and asymmetric dimethylarginine (ADMA). The findings suggest that D1-induced vasorelaxation through the PI3K/Akt/eNOS/NO/cGMP/PKG pathway by activating the KCa, Kir and KV channels or muscarinic and β-adrenergic receptors, and inhibiting the l-type Ca2+ channels, which is closely related to the hypotensive action of the agent. Furthermore, D1 exhibits an inhibitory effect on vascular inflammation, which is associated with the observed vascular protective effects.

Study on the vasodilatory activity of lotus leaf extract and its representative substance nuciferine on thoracic aorta in rats

Lotus (Nelumbo nucifera) leaves are widely used for both edible and medicinal applications. For its further utilization, we studied the vasodilatory activity of lotus leaf extract for the first time. In this study, we obtained the extracts using different ratios of water and ethanol, which was followed by polarity-dependent extraction. We found that the CH₂Cl₂ layer exhibited better vasodilatory activity (EC₅₀ = 1.21 ± 0.10 μg/ml). HPLC and ESI-HRMS analysis of the CH₂Cl₂ layer using the standard product as a control revealed that nuciferine (E_max = 97.95 ± 0.76%, EC₅₀ = 0.36 ± 0.02 μM) was the main component in this layer. Further research revealed that nuciferine exerts a multi-target synergistic effect to promote vasodilation, via the NO signaling pathway, K⁺ channel, Ca²⁺ channel, intracellular Ca²⁺ release, α and β receptors, etc. Nuciferine exhibits good vasodilatory activity, and it exhibits the potential to be utilized as a lead compound.

Xanthotoxin (8-methoxypsoralen): A review of its chemistry, pharmacology, pharmacokinetics, and toxicity

Xanthotoxin (XAT) is a natural furanocoumarins, a bioactive psoralen isolated from the fruit of the Rutaceae plant Pepper, which has received increasing attention in recent years due to its wide source and low cost. By collecting and compiling literature on XAT, the results show that XAT exhibits significant activity in the treatment of various diseases, including neuroprotection, skin repair, osteoprotection, organ protection, anticancer, antiinflammatory, antioxidative stress and antibacterial. In this paper, we review the pharmacological activity and potential molecular mechanisms of XAT for the treatment of related diseases. The data suggest that XAT can mechanistically induce ROS production and promote apoptosis through mitochondrial or endoplasmic reticulum pathways, regulate NF-κB, MAPK, JAK/STAT, Nrf2/HO-1, MAPK, AKT/mTOR, and ERK1/2 signaling pathways to exert pharmacological effects. In addition, the pharmacokinetics properties and toxicity of XAT are discussed in this paper, further elucidating the relationship between structure and efficacy. It is worth noting that data from clinical studies of XAT are still scarce, limiting the use of XAT in the clinic, and in the future, more in-depth studies are needed to determine the clinical efficacy of XAT.